He watches her exam from the usual place where they talked, where they bonded, where they kissed. The watchtower.
In a way, Howl refers it as his watchtower, maybe their watchtower, though it doesn’t belong to them. It may as well belong to them, Howl thinks with as he tries to guess which blasts of fire are Korra’s and which are her opponent’s. It’s hard to tell at first, but as soon as a victor becomes clear to him, he knows it’s Korra. Even if she is a small speck in his vision, it’s obvious.
Eventually, the sparring dies down. There’s a final blast of fire, and he watches one of the sparring opponents get lodged into the roof of the pagoda—a slight smirk crosses Howl’s face. He knows they’re probably some of the best firebenders in the world—handpicked for the final sparring test—and they still couldn’t hold up against her.
It’s to be expected.
Confident that she has passed, Howl diverts his attention to the horizon. He’ll know for sure soon.